At present, people's material lives are improving faster and faster, and most people have increasingly demanding requirements for their own security. When people are in a dangerous state, it is a concern of the people how to tell others the dangerous state and ensure their own security. At present, performing an alarm operation by mobile phones is very convenient. However, when the alarm operation is performed through a communication device such as a mobile phone, it is needed to manually input information and set contacts, which may waste time and may likely make it impossible to perform the alarm operation due to restrictions of current environments. Therefore, performing the alarm operation by mobile phones is not convenient enough.